From the time that gramophone recordings were first sold to the public until the distribution of music recordings became dominated by Internet download technology, users have organized their collections of music recordings simply by organizing the media objects themselves—78s, 45 singles, 33⅓ long play albums, 8-track tape cartridges, cassette tapes, and compact disks—and by mechanically placing these physical objects into a playback machine in a sequence. By placing many songs on a single recording medium, the recording industry provided an intermediate level of organization with 20 minutes to 45 minutes of music recordings in a sequence recorded on the recording media.
However, with the advent of digital file-sharing and similar services, audiophiles are now acquiring large numbers of individual music recordings of one to five minutes in length. Because hard disk storage has become inexpensive, audiophiles are building libraries of thousands of these recordings. The intermediate level of organization previously provided by the recording industry is not available. The listener must make approximately 15 to 30 selection decisions for each hour of music played.